1. Field of the Invention
The present invention relates to a method of transmitting feedback information, and more particularly, to a method of transmitting feedback information using an extended subheader.
2. Discussion of the Related Art
FIG. 1 is an example illustrating a structure of a Medium Access Control (MAC) Protocol Data Unit (PDU). As illustrated in FIG. 1, the MAC Management PDU includes a MAC Header 11, a Management Message Type 12, and a MAC Management Payload 13. Furthermore, a Bandwidth Request PDU is used by each user to dynamically request a necessary bandwidth for transmitting uplink data. The Bandwidth Request PDU is special in that it only includes the bandwidth request header and nothing else including a payload.
FIG. 2 illustrates a structure of the MAC PDU of FIG. 1. More specifically, if a MAC PDU is formed without packing or fragmenting a MAC Service Data Unit (SDU), as illustrated in FIG. 2, a MAC PDU does not included a packing subheader or a fragmentation subheader.
FIG. 3 illustrates another example of a structure of a MAC PDU. As illustrated in FIG. 3, a MAC SDU 31 is fragmented to be included in forming two or more MAC PDUs 30a and 30b. In forming the MAC PDUs 30a and 30b, fragmentation subheaders 34a and 34b are attached behind the MAC headers 33a and 33b, respectively. Moreover, MAC SDUs 35a and 35b are attached behind the fragmentation subheaders 34a and 34b, respectively, to form MAC PDUs 30a and 30b. 
FIG. 4 is yet another example illustrating a structure of a MAC PDU. In FIG. 4, a MAC PDU is formed by packing two or more MAC SDUs (e.g., MAC SDU #1 41a and MAC SDU #2 41b). These MAC SDUs 44 and 46 are attached behind packing subheaders 43 and 46, respectively. Here, the MAC PDU has a MAC header 42 in front and more specifically, in front of the packing subheader 43.
As described above, when the MAC SDU is fragmented or packed, fragmentation subheader or packing subheader is attached to the respective MAC PDU(s). As such, the MAC PDU can be classified in its respective units and according to frame numbers.
In the conventional art, only the methods related to fragmenting and packing are available. In other words, the conventional art does not include a MAC PDU structure having various expanded subheaders.